Counties have been told they have until the end of May to propose changes to the ECB's visa criteria for overseas players, after a challenging offseason for directors of cricket.

Securing high-quality overseas players has never been harder for counties due to a congested domestic schedule, overlaps with an increasing number of franchise leagues and the unique challenge of a T20 World Cup in the middle of the English summer. As a result, many counties have brought in relatively unheralded overseas players this year.

Many players would not have qualified for a visa under previous criteria but the ECB successfully lobbied the UK Home Office for a change in 2019. While visa criteria were previously linked exclusively to international caps, they have opened up so that players who have played 20 T20s in a full-member country in the previous three years are eligible.

While the change has created a new route for a number of overseas players to qualify for a visa to play in county cricket, it has led to some unusual situations. One player agent said: "Some of our clients would have had opportunities to play Division One cricket in the County Championship, but they didn't qualify for a visa due to the current T20-based criteria."

The ECB has an annual consultation period in which counties can propose changes to existing criteria. The governing body has no immediate plan to change the criteria but would listen to any proposals. These would then be sent to the ECB's board for approval and be presented to the Home Office.

Any change would need to satisfy the Home Office requirement that players looking to obtain a visa should "make a significant contribution to the development of their sport at the highest level in the UK".

Cook said: "The danger with opening it up too much is that you end up blocking opportunities for academy or second-team players that might otherwise get opportunities, and they end up drifting out of the game. You want overseas players coming over that will add value, and drive your existing group forwards."

"A baptism of fire is a good way of putting it," said Cook, who became director of cricket at the end of last season after four years as the club's bowling coach. "The window for players to be available for county cricket has shrunk significantly it has been a perfect storm and there have been some significant challenges for us."